The present invention relates to a tamper evident shrink band for use in sealing a cap to a container.
Packaging articles such as foods and drugs requires a consideration of traditional concerns related to preventing passive contamination by bacteria and other contaminants from the environment. Packaging of the articles, unfortunately, also requires a consideration of preventing active contamination caused by human tampering of articles to be ingested.
A package designer must then consider not only how to contain and seal an article that is ingested but must also consider how to signal to a user that tampering has occurred. The signal itself must deter tampering. Satisfying these two criteria has frequently involved designing two separate mechanisms. A first mechanism addresses only a sealing function of the packaging. A second mechanism addresses only the tamper signal function.
This two mechanism approach to packaging has provided an intermediate solution to sealing and package security. However, the approach has produced inefficient packaging because an excessive quantity of materials has been required to make the two mechanisms. Additionally, this approach to packaging has frequently been inconvenient to the end user because the user must separately figure out how to breach each of the sealing mechanism and the tamper proof mechanism.
The Ewan patent, U.S. Pat. No. 5,294,470, issued Mar. 15, 1994, describes a tamper proof sealing container and a seal. The Ewan patent describes a band having an inner surface with a masking material disposed in an indicia-defining pattern on the inner surface. The masking material adheres to the inner surface of the band. A colorant layer overlays the masking material. An adhesive is applied over the colorant layer.
The Ewan patent further includes a container holding articles having a surface and a flap. The flap has a window that registers with the surface of the container when the flap is closed.
The inner surface of the band has a relatively greater adhesion to the colorant layer than the masking layer. When the inner surface of the band applied to a container is lifted away from a container surface, the unmasked colorant layer is removed with the inner surface of the band leaving the masking material and colorant layer beneath the masking material on the container holding the articles. The inner surface of the band, lacking adhesive, then prevents the seal from being replaced in its original condition. Consequently, the seal irreversibly indicates when it is opened.
The Butler patent, U.S. Pat. No. 4,865,198, issued Sep. 12, 1989, describes a method for imprinting an image on an interior surface of an overcap film by vaporizing ink from an underlying inner surface. An activating energy source such as a pulsed laser beam is used to imprint words or symbols on the film by vaporizing ink or pigment from the underlying substrate. The vaporized ink transfers in register to an inside surface of the overcap. Unless one of the film and overcap surfaces is moved with respect to the other, no tamper-evident indicia appear to be present in the overcap package structure.
The Kenyon 2nd patent, U.S. Pat. No. 4,782,976, issued Nov. 8, 1988, describes a tamper evident plastic canister, with plastic snap-on reclosure lid and shrink band assembly. The canister includes a canister body and a rim. The rim enables reclosure of the canister with the snap-on lid. The shrink band engages a sidewall of each of the lid and canister. The shrink band is positioned about the lid and canister and then shrunk into place. The shrink band is scored in a manner that reveals attempts to remove the shrink band from the canister and lid. The tampering attempts become identifiable in the form of visible fractures or tears in the shrink band.
The Kenyon 2nd patent, U.S. Pat. No. 4,813,559, issued Mar. 21, 1989, describes a tamper-evident closure that includes a shrink band for a container with a rim and a lid secured to the container around the rim. The tamper-evident closure includes a label bonded to each of the container and the shrink band. The label includes a weakened line such as a line of perforations encircling the label just below the lower edge of the shrink band. Additional adhesive below this perforated line will bond the remainder of the label to the body of the container. When the shrink band is torn away from the container, the shrink band carries with it the upper portion of the label.
The Faust et al. patent, U.S. Pat. No. 5,111,953, issued May 12, 1992, describes a lid assembly. The lid assembly includes a lid having a lower rim and a seal strip that is irreversibly attached to the lower rim. The seal strip includes a first heat shrinkable section. The seal strip extends circumferentially around the rim. The seal strip also includes a strip of pressure-sensitive adhesive tape and a second heat shrinkable section.